You are supposed to call the DOW and have them take the carcass. It will be up to the game warden that comes if you can keep the rack. Generally, they don't allow it. If you get caught with it later with no tag filled, and no supporting documentation you can be charged with poaching.

They generally don't let you keep the rack or any meat, because there is no way for you to prove that you didn't kill/wound it. So allowing you to keep the rack provides a loop-hole for poaching, whenin some shady person shots a bull for the rack illegally, then reports it as a found carcass, doesn't get charged but gets to keep the rack.